I have created a relatively straight-forward model on an Excel spreadsheet for doing some tax related calculations.
The model requests four different input figures from the user, has some built-in background assumptions (it should be relatively easy to change these assumptions in the future) and then calculates ten different scenarios using the inputs and the assumptions and picks up the most "advantageous" scenario and prints out some results related to the scenario.
You'll need a reasonably good knowledge of Excel functions.
The scope of this project only includes the script file for receiving the inputs, making the calculations and returning the result as well as a simple html page to present the functioning of the script. The actual front-end will be made separately.
Please indicate which language you would prefer to use for this and shoot me a PM and I'll provide you with the spreadsheet.
Payment by PayPal after the product is finished.